Another superb comment, an extract of which puts it better than I could ever hope to:
Many Broads pubs can and do survive largely on trade during the summer season, provided that the premises costs, capital or rental, are reasonable. There is good reason to suppose that the capital value and tenancy rental attached to the premises by the current owner are higher than can be justified by the likely trade and do not fully reflect the access problems. Unrealistic premises costs should not be a reason for claiming the pub to be unviable and so justify its conversion to a dwelling house.
Excellent comment IMHO